Lubricant system for reducing frictional noise

ABSTRACT

A lubricant system for reducing frictional noise includes: a textile fabric at least partially embedded in a lubricant, the lubricant including a comb polymer having a main polymer chain and a plurality of side chains covalently bonded to the main polymer chain. At least one of the side chains has a molecular weight of at least 60 g/mol and/or at least 5 repeat units.

CROSS-REFERENCE TO PRIOR APPLICATION

Priority is claimed to German Patent Application No. DE 10 2018 131931.2, filed on Dec. 12, 2018, the entire disclosure of which is herebyincorporated by reference herein.

FIELD

The invention relates to a lubricant system for reducing frictionalnoise, in particular in the car interior. The invention further relatesto a method for producing the lubricant system and to its uses.

BACKGROUND

Frictional noises that arise when surfaces (e.g. plastic surfaces) rubagainst one another, such as squeaking noises in the car interior, arehighly undesirable, since they drastically reduce the impression of highquality, particularly in the case of high-priced products. Suchfrictional noises are produced by the surfaces rubbing against eachother, in particular by static friction that is sometimes very high,which prevents the surfaces from sliding on each other. This effect isdescribed as stick-slip effect in detail in the technical literature[“Origin of Stick-Slip Motion in Boundary Lubrication,” Science 1990,250, 792-794, doi:10.1126/science. 250.4982.792]. In order to reducefrictional noise, using noise-inhibiting textile tapes is known. Suchtapes are applied between the surfaces rubbing against each other andthereby reduce noise development. However, they are disadvantageous inthat they significantly increase the distance between the surfaces. Afurther disadvantage is that they do not work in all frictionsituations, since their friction-reducing properties are not independentof speed and force.

Using PFPE-based lubricating greases in order to avoid creaking noisesin door seals and door profiles, as described, for example, in EP2721126 B1, is also known.

U.S. Pat. No. 9,371,498 B2 describes the production of a lubricantsystem by combining fibers or a fiber network as a carrier substrate andan oil or a lubricating liquid. Fibers that are oleophilic and have anaffinity for the oil or the lubricating liquid are used in this case.Nonwovens fixed to surfaces can, among other things, be used as thefiber network. An essential feature of the lubricant system described isthat a liquid is introduced into the fiber network and is released in acontrolled manner during the lubricating process, for example bychanging the pH value, the TAN value or the temperature.

The disadvantage of the system described is that there is no permanentbinding of the lubricant to the carrier substrate. As a result, thelubricants leak from the carrier material when an external pressurearises, for example. To be sure, leakage of the lubricant in thedescribed system is also necessary to obtain the desired lubricatingeffect. However, this has the disadvantage that the leaked lubricantleads to a negative perception and can diffuse into polymer surfaces. Inaddition, the lubricant is consumed thereby, which leads to shorterservice life and decreasing performance.

U.S. Pat. No. 7,247,587 B2 describes a nonwoven which contains a fibermixture of fluorine-containing and non-fluorine-containing polymerscombined with a thermoset as resin. The friction-reducing effect isessentially due to the low surface energy of the fluorine-containingfibers. A disadvantage of the described system is that it consists of atleast 3 different components, and fluoropolymer fibers are not standardfibers, which makes the system significantly more expensive. Inaddition, fluorine fibers are partially crystalline and thereforecomparatively hard, which reduces their lubricating effect.Fluoropolymers also have disadvantages for environmental reasons. Adisadvantage of thermosets is that they are hard and brittle and cantherefore be integrally formed only with difficulty onto complexgeometries, such as are found, for example, in car interiors. Inaddition, thermosets have undesirable stick-slip behavior with highnoise development.

CN 105328938 A describes a self-lubricating composite material which isa laminate body made of a woven fabric and a fluorine-containing film. Adisadvantage of the composite material described is that fluoropolymershave disadvantages for environmental reasons as described above. Inaddition, they only have a low mechanical strength. Furthermore, thefriction-reducing effect is based only on surface effects, such that itis comparatively minor. In addition, the fluorine film must have acomparatively high thickness (up to 1000 μm) in order to compensate forthe lack of mechanical strength and to provide a satisfactoryfriction-reducing effect.

SUMMARY

In an embodiment, the present invention provides a lubricant system forreducing frictional noise, comprising: a textile fabric at leastpartially embedded in a lubricant, the lubricant comprising a combpolymer having a main polymer chain and a plurality of side chainscovalently bonded to the main polymer chain, wherein at least one of theside chains has a molecular weight of at least 60 g/mol and/or at least5 repeat units.

DETAILED DESCRIPTION

In an embodiment, the present invention provides a lubricant systemwhich at least partially eliminates the aforementioned disadvantages ofthe prior art. In this case, the lubricant system should reduce orpreferably completely eliminate frictional noises that arise whensurfaces, in particular plastics, rub against one another. Moreover, anat least constant or even improved noise reduction is to be achieved incomparison to the known solutions. In addition, the lubricant systemshould preferably have a broad range of applications and reduce noisedevelopment, particularly preferably independently of load, speed andduration of use.

In an embodiment, the present invention provides a lubricant systemcomprising a textile fabric at least partially embedded in a lubricant,wherein the lubricant contains a comb polymer having a main polymerchain and a plurality of side chains covalently bonded to the mainpolymer chain, and wherein at least one of the side chains has amolecular weight of at least 60 g/mol and/or at least 5 repeat units.

In the lubricant system according to the invention, a textile fabric isat least partially embedded in a lubricant which contains at least onecomb polymer with a main polymer chain and a plurality of side chainscovalently bonded to the main polymer chain. In this case, the textilefabric is physically enclosed by the comb polymer and the lubricant isthereby prevented from leaking from the lubricant system. In addition toembedding, a chemical, for example an ionic and/or covalent, bond mayalso be present at least partially.

According to the invention, it was surprisingly found that the lubricantsystem is capable of reducing or completely eliminating frictional noisefrom surfaces, for example plastic surfaces, which rub against oneanother. Risk priority numbers (RPZ) of 1 could thus be obtained withexemplary lubricant systems according to the invention. These resultscould be achieved for a wide variety of friction partners, contactpressures and friction speeds. The excellent tribological properties ofthe lubricant system are presumably based on the lubricant being presentas a noise-damping component in the form of a solid (20° C.). This isadvantageous in comparison to liquid lubricants, since the noise-dampingcomponents are fixed in place and can be particularly effective as aresult.

Moreover, the lubricant system can achieve an at least constant or evenimproved noise reduction in comparison to the known solutions. Inaddition, the lubricant system has a broad range of applications and iscapable of reducing noise development independently of load, speed andduration of use.

The term “lubricant” is understood according to the invention to mean asubstance and/or a mixture of various substances which are suitable forlubricating and/or reducing friction and wear of surfaces rubbingagainst each other, for example of plastic parts in the motor vehicleinterior. Advantageously, the lubricant additionally serves for forcetransmission, cooling, vibration damping, sealing effect and preventionof corrosion.

According to the invention, the lubricant comprises a comb polymer witha main polymer chain and a plurality of side chains covalently bonded tothe main polymer chain.

The term “plurality of side chains” is to be understood according to theinvention as meaning that at least two repeat units of the main chainhave at least one of the side chains according to the invention. Thecomb polymer preferably has 2 to 10000, more preferably 50 to 3000, morepreferably 100 to 2000, of the side chains according to the invention.Preferably at least 10%, for example 10% to 100%, preferably 20% to100%, more preferably 50% to 100%, in particular 80% to 100%, of therepeat units of the main chain have at least one, preferably one to two,of the side chains according to the invention. In a further preferredembodiment of the invention, [ . . . ] have [ . . . ].

The term “main polymer chain” is understood according to the inventionto be the longest covalently bonded chain of atoms of a polymer. Themain polymer chain preferably has a molecular weight of at least 580g/mol, for example from 580 g/mol to 50,000 g/mol, more preferably from1000 g/mol to 20,000 g/mol, more preferably from 1500 g/mol to 10,000g/mol, and/or at least 8, for example 8 to 2000, preferably 25 to 1000,in particular 25 to 500, repeat units.

The term “side chain” is understood according to the invention to mean apolymer chain and/or oligomer chain which is covalently bonded to themain polymer chain, the chain length of which is shorter than that ofthe main polymer chain. The side chain preferably has a molecular weightof at least 60 g/mol, preferably from 60 g/mol to 2500 g/mol, preferablyfrom 220 g/mol to 2500 g/mol, preferably from 360 g/mol to 2000 g/mol,more preferably from 450 g/mol to 1500 g/mol, more preferably from 600g/mol to 1500 g/mol, in particular 700 g/mol to 1500 g/mol, and/or atleast 5, for example 5 to 100, preferably 8 to 50, in particular 8 to20, repeat units.

In a preferred embodiment of the invention, the main polymer chain hason average at least 3, for example 3 to 2000, preferably 10 to 1000,more preferably 50 to 500, in particular 50 to 250, side chains. In thiscase, different main chains may have different numbers of side chains.

Furthermore, the comb polymer, the main polymer chain and/or the sidechain preferably have a glass transition temperature as measured by DSCaccording to DIN EN ISO 11357-2 (edition: 2014-07) at a heating rate of10° C./minute, from −40° C. to 80° C., preferably from −20° C. to 70°C., preferably from −20° C. to 60° C., in particular −20° C. to 40° C.Rather low glass transition temperatures are advantageous in that thelubricant generally has better lubricating properties than in the caseof higher glass transition temperatures.

In a preferred embodiment of the invention, the side chain of the combpolymer comprises a base oil. The term “base oil” is to be understood asmeaning the customary base liquids used for the production oflubricants, in particular oils which can be assigned to the groups I,II, II+, III, IV or V in accordance with the classification of theAmerican Petroleum Institute (API), [NLGI Spokesman, N. Samman, volume70, number 11, pages 14 et seq.]. Particularly preferred base oils areselected from the group consisting of esters, ethers, in particularpolyglycols, phenyl ethers, perfluoropolyethers, mineral oils, synthetichydrocarbons, in particular polyalphaolefins, natural hydrocarbons,native oils and derivatives of native oils, silicone oils and/ormixtures thereof.

Particularly preferred according to the invention are esters, ethers,preferably polyglycol ethers, in particular polyphenyl ethers,polyethylene glycol ethers and/or polypropylene glycol ethers, synthetichydrocarbons, in particular polyalphaolefins and/or mixtures thereof.Very particular preference is given to ethers, preferably polyglycolethers, in particular polyethylene glycol ethers and/or polypropyleneglycol ether.

Preferred esters are carboxylic esters, especially monoesters, diesters,triesters, tetraesters, pentaesters, polyesters, aromatic esters andmixtures thereof. The carboxylic esters preferably have a chain lengthof C4 to C22.

In a preferred embodiment of the invention, the base oil is selectedfrom the group consisting of an ester of an aromatic and/or aliphaticdicarboxylic, tricarboxylic or tetracarboxylic acid having one or amixture of C7 to C22 alcohols, of an ester of trimethylene propane,pentaerythritol or dipentaerythritol with aliphatic C7 to C22 carboxylicacids, of an ester of C18 dimer acids with C7 to C22 alcohols, complexesters, as individual components or in any mixture.

Preferred ethers are polyglycol ethers, in particular polyethyleneglycol ethers and/or polypropylene glycol ethers. These ethers may bebranched or unbranched. Unbranched polyglycol ethers are preferablyused.

Preferred synthetic hydrocarbons are polyalphaolefins. Polyalphaolefinsare generally mixtures of oligomers or polymers consisting of an aolefin or isomerized a olefin. Examples of the a olefin are 1-octene,1-nonene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene,1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene,1-eicosene, 1-docosene and 1-tetradocosene. Mixtures of these substancesare normally used.

In a preferred embodiment, the fluorine content, determined byelementary analysis, in the lubricant system is less than 10 wt. %, morepreferably less than 5 wt. %, in particular less than 1 wt. %, based onthe total weight of the lubricant system. This is possible according tothe invention, since the lubricant system has excellent lubricatingproperties even without fluoropolymers.

The comb polymer can be obtained by polymerizing a macromonomer havingpolymerizable functionalities as a precursor. The term “macromonomer” isto be understood as meaning a monomer which has a molecular weight of atleast 140 g/mol, for example from 140 g/mol to 2600 g/mol, preferablyfrom 220 g/mol to 2600 g/mol, preferably from 360 g/mol to 2000 g/mol,more preferably from 450 g/mol to 1500 g/mol, more preferably 600 g/molto 1500 g/mol, in particular 700 g/mol to 1500 g/mol. The macromonomermay have monomers of the same and/or different chemical structure. Themacromonomer is preferably a base oil, in particular a base oil asdefined above.

In addition to the macromonomer, other monomers, for examplecommercially available acrylates and/or methacrylates, can also be usedto produce the comb polymer. In order to ensure polymerizability for thecomb polymer, the macromonomer contains at least one polymerizablefunctionality. If the macromonomer at least partially contains more thanone polymerizable functionality, the macromonomer can crosslink duringpolymerization and thus impart a higher mechanical stability to the combpolymer formed. Thus, in a preferred embodiment, the macromonomer has atleast partially 2 to 10, more preferably 2 to 5, particularly preferably2 to 3, polymerizable functionalities. Furthermore, in a furtherpreferred embodiment, the macromonomer has at least partially 2 to 10,more preferably 2 to 5, particularly preferably 2 to 3, polymerizablefunctionalities and at least partially only one polymerizablefunctionality. For example, if one portion of the macromonomers has onlyone polymerizable functionality and another portion has twopolymerizable functionalities, the macromonomers having twopolymerizable functionalities enable crosslinking, while themacromonomers having one polymerizable functionality positivelyinfluence the lubricating properties. Various macromonomers, each ofwhich may have different base oils and/or different polymerizablefunctionalities, may be used to produce the comb polymer. It was foundthat the good lubricating properties of the base oil can be preserveddespite polymerization.

In a further preferred embodiment of the invention, the comb polymer istherefore crosslinked. The term “crosslinking” is understood accordingto the invention to mean the formation of a two-dimensional and/orthree-dimensional network by physical and/or chemical linking ofmolecules. Crosslinking can take place by reaction of a main polymerchain with a main polymer chain, of a main polymer chain with a sidechain, of a side chain with a side chain and/or a combination thereof.Crosslinking generally reduces the solubility of the lubricant. This isadvantageous, since the mechanical stability of the lubricant can thusbe increased and the risk of leakage from the textile fabric can bereduced. Crosslinking of the comb polymer thus manifests, for example,in the crosslinked comb polymer no longer being soluble in a solvent inwhich the macromonomer is soluble.

The macromonomer can be introduced into the textile fabric in the liquidstate, as a result of which the fibers of the textile fabric can besurrounded by the macromonomer and be embedded therein. The macromonomercan be applied to one or both surfaces of the textile fabric as acoating and/or at least partially in the interior of the textile fabric,wherein the lubricant can also have a distribution gradient.Polymerizing the macromonomer results in the macromonomer hardening,whereby mechanical fixing of the textile fabric can be achieved.

Suitable polymerizable functionalities are known to the person skilledin the art. The polymerizable functionalities can preferably bepolymerized by means of free-radical, ionic polymerization, polyadditionand/or polycondensation. The polymerizable functionalities arepreferably polymerizable by free-radical polymerization. Particularlysuitable polymerizable functionalities are selected from the groupconsisting of acrylamide, acrylate, methacrylate, vinyl ether, vinylester, (di)alkyl fumarates, (di)alkyl maleates, maleimide, styrene,alpha-olefin functionalities and combinations thereof. Particularlysuitable polymerizable functionalities are acrylamide, acrylate,methacrylate and/or vinyl ether functionalities. A particularly suitablemacromonomer is selected from the group consisting of ethers, inparticular polyglycols and/or esters which have one or more(meth)acrylate functionalities.

In a preferred embodiment, the ratio of macromonomer functionalized witha polymerizable functionality to macromonomer functionalized with atleast 2 polymerizable functionalities is preferably from 100 wt. %/1 wt.% to 1 wt. %/100 wt. %, more preferably from 98 wt. %/2 wt. % to 25 wt.%/75 wt. %, more preferably from 95 wt. %/5 wt. % to 60 wt. %/40 wt. %.

The lubricant may be present on one or both surfaces of the textilefabric as a coating and/or at least partially in the interior of thetextile fabric, wherein the lubricant may also have a distributiongradient. According to the invention, the lubricant is preferablypresent at least partially in the interior of the textile fabric. Thisis advantageous since, when the lubricant system is used, for examplewhen it is inserted between plastic surfaces in the car interior, noleakage of lubricant occurs even with continued loading and mechanicalwear occurring in the process. As a result, the lubricant obtains goodmechanical strength.

According to the invention, lubricant preferably does not leak in thelubricant system even at a load below room temperature at pressures of0.1 to 1000 N/cm².

This is advantageous, since leakage of lubricant during use degrades thelubricating effect. In addition, leaking liquid lubricants reduce theoptical impression of a component and can be detected by olfactorymeans.

A further advantage of the lubricant system according to the inventionis that a textile fabric is used instead of loose fibers, since it has ahigher mechanical strength.

The term “textile fabric” is understood according to the invention tomean a fabric which is produced from textile raw materials using textiletechnology. Textile raw materials can be fibers, filaments, pulp andmixtures thereof. Preferred textile fabrics are woven fabrics,warp-knitted fabrics, knitted fabrics, felts, braids, nets, fibrous websand/or nonwovens. Nonwovens are particularly preferred, since they canbe produced in a simple manner with isotropic mechanical strengthdistribution. This is advantageous for use for minimizing noise, sincethe effect is not dependent on the installation direction of thelubricant system. Nonwovens can be spunbond nonwovens, meltblownnonwovens, wet nonwovens, dry nonwovens, nanofiber nonwovens andnonwovens spun from solution. In one embodiment, spunbond nonwovens arepreferred, since they can be provided with a high mechanical strength bythe targeted adjustment of the distribution of the fiber thicknesses. Ina further embodiment, meltblown nonwovens are preferred, since they canbe provided with a low fiber thickness and a very homogeneousdistribution with respect to the fiber thicknesses. In a furtherembodiment, dry nonwovens are preferred, since they have a high tensilestrength of the fibers. In a particularly preferred embodiment, thetextile fabric is a wet nonwoven, since it can be produced with a veryuniform fiber distribution, a low weight and a uniform thickness of thefibers.

Preferably, the textile fabric has a thickness of 15 μm to 500 μm, morepreferably of 30 μm to 500 μm, more preferably of 45 μm to 200 μm, morepreferably of 60 μm to 150 μm.

The textile fabric also preferably has a weight of 10 g/m² to 500 g/m²,more preferably 35 g/m² to 500 g/m², more preferably 45 g/m² to 200g/m², in particular 45 g/m² to 100 g/m².

The nonwoven, in particular in its embodiment as a wet nonwoven, maycomprise staple fibers and/or short-cut fibers. According to theinvention, unlike filaments that have a theoretically unlimited length,staple fibers are fibers that have a limited length, preferably of 1 mmto 80 mm, more preferably of 3 mm to 30 mm. According to the invention,short-cut fibers are fibers with a length of preferably 1 mm to 12 mm,more preferably 3 mm to 6 mm. The mean titer of the fibers may varydepending on the desired structure of the nonwoven. The use of fibershaving a mean titer of 0.06 dtex to 3.3 dtex, preferably of 0.06 dtex to1.7 dtex, preferably of 0.1 dtex to 1.0 dtex, in particular proved to beadvantageous.

Practical tests have shown that the at least partial use of microfibershaving a mean titer of less than 1 dtex, preferably of 0.1 dtex to 1dtex, has an advantageous effect on the size and structure of the poresizes and inner surface and also on the density of the nonwoven.Proportions of at least 5 wt. %, preferably of 5 wt. % to 25 wt. %,particularly preferably of 5 wt. % to 10 wt. % of microfibers, based ineach case on the total amount of fibers in the nonwoven, proved to beparticularly favorable. It was thus found in practical experiments thata particularly stable encapsulation of the fibers with the lubricant andthereby a particularly wear-resistant lubricating effect can be achievedwith the aforementioned parameters.

The fibers can have a wide variety of shapes, for example be flat,hollow, round, oval, trilobal, multilobal, bicomponent, and/orislands-in-sea fibers. According to the invention, the cross-section ofthe fibers is preferably round.

According to the invention, the fibers may contain a wide variety offiber polymers, preferably polyacrylonitrile, polyvinyl alcohol,viscose, cellulose, polyamides, in particular polyamide 6 and polyamide6.6, polyesters, copolyesters, polyolefins, in particular polyethyleneand/or polypropylene, and/or mixtures thereof. Polyesters and/orpolyolefins, in particular polyethylene and/or polypropylene, arepreferred.

The use of polyesters has the advantage that they have a high mechanicalstrength. The use of polyolefins has the advantage that they can furtherimprove the lubricating effect of the lubricant system according to theinvention based on their hydrophobic surface.

The fibers advantageously contain the aforementioned materials in aproportion of more than 50 wt. %, preferably more than 90 wt. %, morepreferably 95 wt. % to 100 wt. %. Very particularly preferably, theyconsist of the above-mentioned materials, it being possible for theusual impurities and auxiliary agents to be present.

The fibers of the nonwoven may be in the form of matrix fibers and/orbinding fibers. Binding fibers within the meaning of the invention arefibers which, for example during the production process of the nonwoven,can form solidification points and/or solidification regions at least atsome intersection points of the fibers as a result of heating to atemperature above their melting point and/or softening point. At suchintersection points, the binding fibers can form firmly bondedconnections to other fibers and/or to themselves. The use of bindingfibers thus makes it possible to construct a framework and to obtain athermally solidified nonwoven. Alternatively, the binding fibers canalso melt completely and solidify the nonwoven in this way. The bindingfibers can be formed as core-sheath fibers, in which the sheathconstitutes the binding component, and/or as non-drawn fibers.

Matrix fibers within the meaning of the invention are fibers which,unlike binding fibers, are present in a significantly clearer fiberform. An advantage of the presence of the matrix fibers is that thestability of the fabric as a whole can be increased.

In a preferred embodiment of the invention, the ratio between lubricantand textile fabric in the lubricant system is 1 wt. % to 1000 wt. %,preferably 1 wt. % to 500 wt. %, more preferably 10 wt. % to 200 wt. %,more preferably 80 wt. % to 160 wt. %, based in each case on the weightof the textile fabric. It was found that a good lubricating effect withgood mechanical adaptability can be achieved with these ratios.

In a further preferred embodiment of the invention, the weight of thelubricant system, measured according to test specification DIN EN 29073,is from 15 g/m² to 600 g/m², more preferably from 50 g/m² to 300 g/m²,more preferably from 50 g/m² to 180 g/m².

In a further preferred embodiment of the invention, the thickness of thelubricant system, measured according to test specification EN 29073-T2,is from 15 μm to 600 μm, more preferably from 50 μm to 600 μm, morepreferably from 60 μm to 500 μm, more preferably from 60 μm to 300 μm.

It was surprisingly found according to the invention that a goodlubricating effect can be achieved even at low thicknesses. This isadvantageous when used in the car interior, for example for opticalreasons. Furthermore, the small thickness is advantageous in thatmechanical loads can be minimized as a result.

The lubricant system according to the invention preferably has pores atleast partially. The pores may be open or closed pores. The proportionof open pores can be determined by air permeability measurements. In apreferred embodiment of the invention, the air permeability of thelubricant system, measured according to test specification DIN EN ISO9237, is 0 l/m²*s to 1000 l/m²*s, more preferably 10 l/m²*s to 500l/m²*s, more preferably 25 l/m²*s to 300 l/m²*s.

The pores are advantageous, since they provide the lubricant system withan uneven surface. As a result, the surface has a smaller number offrictional contacts than a smooth surface, which in turn leads to alower static friction. The uneven surface has a plurality of smallfrictional contacts, which in turn results in lower static friction thana very large frictional contact in the case of a smooth surface.

In a further embodiment of the invention, the lubricant system accordingto the invention is single-layered, i.e., there are no physical phaseboundaries within the lubricant system. This is advantageous, since nocomponents that are inoperable for the lubricating effect are used inthis way.

In a preferred embodiment of the invention, the lubricant system isequipped on at least one side with an adhesive layer, for example apolyacrylate and/or natural rubber.

The lubricant system according to the invention has excellentfrictional-noise-reducing properties. Thus, in one embodiment of theinvention, the risk priority number of the lubricant system with aplastic as friction partner, measured according to the VDA 203-206standard at a speed of 1 mm/s to 10 mm/s and a normal force of 5 N to 20N, is 1 to 5, preferably 1 to 3, more preferably 1 to 2.

In a further preferred embodiment of the invention, the risk prioritynumber of the lubricant system with a polycarbonate/acrylonitrilebutadiene styrene copolymer (PC/ABS) blend as friction partner, measuredaccording to the VDA 203-206 standard at a speed of 1 mm/s to 10 mm/sand a normal force of 5 N to 20 N, is 1 to 5, more preferably 1 to 3, inparticular 1 to 2.

In a further preferred embodiment of the invention, the risk prioritynumber of the lubricant system with polyurethane (Beneron®) as frictionpartner, measured according to the VDA 203-206 standard at a speed of 1mm/s to 10 mm/s and a normal force of 5 N to 20 N, is 1 to 5, morepreferably 1 to 3, in particular 1 to 2.

The lubricant may exclusively consist of the comb polymer. However, thelubricant preferably contains customary additives, such as anticorrosionadditives, metal deactivators, antiwear additives and/or ion complexingagents.

The lubricant may furthermore contain solid lubricants. In principle,the lubricant may contain thickeners. However, they can be dispensedwith based on the use of the comparatively viscous comb polymer. Theproportion of thickeners, in particular of metal soaps, metal complexsoaps, bentonites, ureas, silicates, sulfonates, polyimides, ispreferably less than 20 wt. %, more preferably less than 10 wt %, inparticular less than 2 wt. %.

The proportion of comb polymer in the lubricant is preferably 30 wt. %.to 100 wt. %, more preferably 75 wt. % to 100 wt. %, in particular 90wt. % to 100 wt. %.

The invention further relates to a method for producing a lubricantsystem comprising a textile fabric embedded in a lubricant, comprisingthe following method steps:

-   -   1. Providing a textile fabric;    -   2. Impregnating and/or coating the textile fabric with a        macromonomer-containing coating composition, the macromonomer        having a molecular weight of at least 140 g/mol, for example of        140 g/mol to 2600, preferably of 220 g/mol to 2600 g/mol,        preferably of 360 g/mol to 2000 g/mol, more preferably of 450        g/mol to 1500 g/mol, more preferably of 600 g/mol to 1500 g/mol,        in particular of 700 g/mol to 1500 g/mol;    -   3. Polymerizing the macromonomer to form a comb polymer having a        main polymer chain and a plurality of side chains covalently        bonded to the main polymer chain, at least one of the side        chains having a molecular weight of at least 60 g/mol, for        example 60 g/mol to 2500 g/mol , preferably 220 g/mol to 2500        g/mol, preferably 360 g/mol to 2000 g/mol, more preferably 450        g/mol to 1500 g/mol, more preferably 600 g/mol to 1500 g/mol, in        particular 700 g/mol to 1500 g/mol, with a lubricant being        formed in which the textile fabric is embedded, forming the        lubricant system.

Preferred features, such as especially preferred macromonomer, textilefabrics and further components of the lubricant system, are thosedescribed within the scope of the invention with regard to the lubricantsystem according to the invention.

The macromonomer used in impregnation and/or coating has a molecularweight of at least 140 g/mol, preferably 140 g/mol to 2600 g/mol,preferably 220 g/mol to 2600 g/mol, preferably 360 g/mol to 2000 g/mol,more preferably 450 g/mol to 1500 g/mol, more preferably 600 g/mol to1500 g/mol, in particular 700 g/mol to 1500 g/mol. The macromonomer mayhave monomers of the same and/or different chemical structure. Themacromonomer is preferably a base oil, in particular a functionalizedbase oil as defined above.

In addition to the macromonomer, other monomers, for examplecommercially available acrylates and/or methacrylates, can also be usedto produce the comb polymer. In order to ensure polymerizability to thecomb polymer, the macromonomer has at least one polymerizablefunctionality. Suitable polymerizable functionalities are thosementioned above in relation to the lubricant system. If the macromonomerat least partially contains more than one polymerizable functionality,the macromonomer can crosslink during polymerization and thus impart ahigher mechanical stability to the comb polymer formed. Thus, in apreferred embodiment, the macromonomer has at least partially 2 to 10,more preferably 2 to 5, particularly preferably 2 to 3, polymerizablefunctionalities. Various macromonomers respectively selected fromdifferent base oils, which may be functionalized with differentpolymerizable functionalities, may be used to produce the comb polymer.

In a preferred embodiment, the ratio of the macromonomer functionalizedwith one polymerizable functionality to the macromonomer functionalizedwith at least 2 polymerizable functionalities, is preferably 100 wt. %/1wt. % to 1 wt. %/100 wt. %, more preferably from 98 wt. %/2 wt. % to 25wt. %/75 wt. %, more preferably from 95 wt. %/5 wt. % to 60 wt. %/40 wt.%.

The coating composition can be applied to one or both surfaces of thetextile fabric as a coating and/or at least partially in the interior ofthe textile fabric, wherein the coating composition can also have adistribution gradient.

The coating composition may exclusively consist of the macromonomer.However, the coating composition preferably contains customaryadditives, such as anticorrosion additives, metal deactivators, antiwearadditives and/or ion complexing agents.

The coating composition can also contain solid lubricants. In principle,the coating composition may contain thickeners. However, they can bedispensed with based on the use of the comparatively viscousmacromonomer. The proportion of thickeners, in particular of metalsoaps, metal complex soaps, bentonites, ureas, silicates, sulfonates,polyimides, is preferably less than 20 wt. %, more preferably less than10 wt %, in particular less than 2 wt. %.

The proportion of macromonomer in the coating composition is preferably50 wt. %. to 100 wt. % and/or 50 wt. % to 90 wt. %, more preferably 75wt. % to 100 wt. % and/or 75 wt. % to 90 wt. %, in particular 80 wt. %to 100 wt. % and/or 80 wt. % to 90 wt. %.

The coating composition may also contain suitable solvents, for examplewater.

The impregnation and/or coating of the textile fabric can be carried outin a conventional manner. Preferred are roll coating methods, padding,dip coating methods, spray coating methods, slot die coating methods,and/or combinations thereof.

Polymerization of the macromonomer can also be carried out in aconventional manner. The macromonomer is preferably polymerized andoptionally crosslinked by means of free-radical, ionic polymerization,polyaddition and/or polycondensation.

Radiation-induced crosslinking methods are particularly preferred.

Subsequent to the polymerization, a drying step may be carried out,preferably at temperatures greater than 30° C., more preferably greaterthan 80° C.

The lubricant system can furthermore be equipped on at least one sidewith an adhesive layer, for example a polyacrylate and/or naturalrubber.

A further subject matter of the present invention is the use of thelubricant system for reducing frictional noise, in particular fromcomponents exposed to frictional loads in the car interior, such asinstrument panels with fittings, door trim with operating elements. Inaddition, the lubricant system can also be used to reduce frictionalnoise from moving cables, for example in aviation. The lubricant systemis preferably introduced between the respective friction partners. In apreferred embodiment, the lubricant system is used simultaneously forreducing frictional noise and for sealing, for example, dynamicallyloaded components.

In the context of the present invention, the following measurementmethods were used:

The weight of the nonwoven was measured according to test specificationDIN EN 29073.

The thickness of the nonwovens according to the invention was measuredaccording to test specification EN 29073-T2.

The invention is explained in more detail with reference to thefollowing examples.

EXAMPLE 1 Production of a Lubricant System According to the Invention

APP wet nonwoven (weight: 50 g/m²; thickness 0.12 mm) is treated with asolution consisting of a mixture of two crosslinkable base oils, namely211 g of a methacrylate-functionalized polyethylene glycol (PEG) (MnPEG: 308 g/mol) and 12.5 g of a PEG diacrylate (Mn PEG: 250 g/mol), 22.8g of water and 2.5 g of a commercially available UV radical initiatorand irradiated for crosslinking with UV light for 45 seconds. Theresulting nonwoven has the crosslinked base oils in the interior and onits surface. The nonwoven is then washed in a water bath and dried at100° C. A lubricant system according to the invention having a thicknessof 0.89 mm and a weight of 121.9 g/m² is obtained. The ratio betweenlubricant and textile fabric in this case is (121.9 g/m²-50 g/m²)/50g/m²=1.438, or 143.8 wt. % of the textile fabric.

EXAMPLE 2 Production of a Lubricant System According to the Invention

A PP wet nonwoven (weight: 50 g/m²; thickness 0.12 mm) is coated with asolution consisting of a mixture of two crosslinkable base oils, namely67.5 g of an acrylate-functionalized polyethylene glycol (Mn PEG: 350g/mol) and 10 g of a PEG diacrylate (Mn PEG: 200 g/mol), 166.3 g ofwater and 5.1 g of a commercially available UV radical initiator andirradiated for crosslinking with UV light for 45 seconds. The resultingnonwoven has the crosslinked base oils in the interior and on itssurface. The nonwoven is then washed in a water bath and dried at 100°C. A lubricant system according to the invention having a thickness of0.121 mm and a weight of 99.1 g/m² is obtained. The ratio betweenlubricant and textile fabric in this case is (99.1 g/m²-50 g/m²)/50g/m²=0.982, or 98.2 wt. % of the textile fabric.

EXAMPLE 3 Production of a Lubricant System According to the Invention

A PP wet nonwoven (weight: 50 g/m²; thickness 0.1 mm) is coated with asolution consisting of a mixture of two crosslinkable base oils, namely211 g of a methacrylate-functionalized polyethylene glycol (Mn PEG: 750g/mol) and 12.5 g of a PEG diacrylate (Mn PEG: 400 g/mol), 99 g of waterand 2.0 g of a commercially available UV radical initiator andirradiated for crosslinking with UV light for 45 seconds. The resultingnonwoven has the crosslinked base oils in the interior and on itssurface. The nonwoven is then washed in a water bath and dried at 100°C. A lubricant system according to the invention having a thickness of0.117 mm and a weight of 99.2 g/m² is obtained. The ratio betweenlubricant and textile fabric in this case is (99.2 g/m²-50 g/m²)/50g/m²=0.984, or 98.4 wt. % of the textile fabric.

EXAMPLE 4 Production of a Lubricant System According to the Invention

A PP wet nonwoven (weight: 57.3 g/m²; thickness 0.105 mm) is coated witha solution consisting of a mixture of two crosslinkable base oils,namely 1387.5 g of a methacrylate-functionalized polyethylene glycol (MnPEG: 818 g/mol) and 150 g of an N,N-methylene-diacrylamide (Mn: 224g/mol), 1387.5 g of water and 60 g of a commercially available UVradical initiator, e.g. Irgacure 369®, and irradiated for crosslinkingwith UV light for 45 seconds. The resulting nonwoven has the crosslinkedbase oils in the interior and on its surface. The nonwoven is thenwashed in a water bath and dried at 100° C. A lubricant system accordingto the invention having a thickness of 0.117 mm and a weight of 86.5g/m² is obtained.

COMPARATIVE EXAMPLE 5 Production of a Lubricant System not According tothe Invention

A PET wet nonwoven (weight 85 g/m², thickness 0.12 mm) is coated with a50% aqueous dispersion of a polyurethane acrylate and dried at 120° C.The polyurethane acrylate is not a comb polymer which has at least oneside chain with a molecular weight of at least 60 g/mol and/or at least5 repeat units. Rather, the side chains preferably have a molecularweight of 500 to 1000 g/mol. During drying, thermal crosslinking of thepolyurethane acrylate occurs. A coated nonwoven having a thickness of0.128 mm and a weight of 145 g/m² is obtained.

EXAMPLE 6 Determination of Relevant Parameters of the Lubricant Systemsand Comparison with Commercial Lubricant Systems

The thicknesses, weights and RPZ numbers of the aforementioned lubricantsystems according to the invention (Examples 1 to 4) are determined andcompared with the following commercial, lubricant systems not accordingto the invention:

-   -   tesa® 51608    -   tesa® 51616    -   3M Conformable Sound Management Film 9343 (3M 9343)

TABLE 1 OVERVIEW OF THE WEIGHTS AND THICKNESSES OF THE VARIOUSLUBRICATION SYSTEMS Weight (g/m²) Thickness (mm) Example 1 121.9 0.89Example 2 99.1 0.104 Example 3 99.2 0.117 Example 4 86.5 0.117Comparative Example 5 145 0.128 tesa ® 51608 0.28 tesa ® 51616 0.65 3M9343 0.58

The aforementioned lubricant systems according to the invention andcomparative examples are evaluated with the aid of the SSP-04 stick-sliptest bench from Zins-Ziegler by determining their RPZ numbers. Testingis carried out according to the VDA 203-206 standard.

The RPZ represents the stick-slip tendency on a scale of 1-10 anddescribes the tendency of a material pairing to stick-slip at apredetermined normal force and a defined speed. Stick-slip is theEnglish term for sliding in a jerking motion. It describes the periodicchange between adhesion and tear-off of two material surfaces movingover each other. It is, for example, the cause of noise phenomena, suchas creaking or squeaking. For the evaluation of a material pairing, anRPZ between 1 and 3 is considered to be non-critical, at 4 or 5 to bestill acceptable. With an RPZ of 6 to 10, the solution to the problem isto be regarded as not given. Unless stated otherwise, the definition ofthe test standard applies. Tensile bars of two materials were selectedas friction partners for the examples and comparative examples: PC-ABSand Beneron®.

TABLE 2 OVERVIEW OF THE RPZS OBTAINED IN MEASUREMENTS AGAINST PC-ABSMeasured parameters Normal Example Example Example Example ComparativeTesa Tesa 3M Speed force 1 2 3 4 Example 5 51608 51616 9343 1 mm/s  5N 11 1 1 3 1 2 2 5 mm/s  5N 1 1 1 1 4 1 2 2 10 mm/s  5N 1 1 1 1 5 1 3 2 1mm/s 10N 1 1 1 1 4 2 2 2 5 mm/s 10N 1 1 1 1 5 2 2 1 10 mm/s 10N 1 1 1 13 2 3 1 1 mm/s 20N 1 1 1 1 3 2 2 2 5 mm/s 20N 1 1 1 1 4 2 1 1 10 mm/s20N 1 1 1 1 4 2 3 1

It can be seen from Table 2 that Examples 1 to 4 according to theinvention result in excellent RPZ values at all measured speeds andnormal forces. In contrast, Comparative Example 5, which does notinclude a comb polymer-containing lubricant, exhibits significantlyworse RPZ values at all measured speeds and normal forces. Thecommercial products also show worse RPZ values at least at some measuredspeeds and normal forces.

TABLE 3 OVERVIEW OF THE RPZS OBTAINED IN MEASUREMENTS AGAINST BENERON ®Measured parameters Normal Example Example Example Example ComparisonTesa Tesa 3M Speed force 1 2 3 4 Example 5 51608 51616 9343 1 mm/s  5N 11 1 2 4 3 2 7 5 mm/s  5N 1 2 2 2 7 7 1 5 10 mm/s  5N 1 2 2 3 5 4 1 3 1mm/s 10N 1 1 2 2 4 6 2 7 5 mm/s 10N 1 2 2 2 6 7 3 5 10 mm/s 10N 1 2 2 37 6 1 4 1 mm/s 20N 1 1 1 2 4 5 2 4 5 mm/s 20N 1 2 2 2 6 4 1 1 10 mm/s20N 1 2 2 2 5 3 1 1

It can be seen from Table 3 that Examples 1 to 4 according to theinvention also result in very good RPZ values with respect to Beneron®as friction partner at all measured speeds and normal forces. The valueswhich are slightly worsened compared to Table 2 are presumably based onthe fact that Beneron® as friction partner has a higher static friction.Furthermore, it is found that Examples 1 to 4 according to the inventionhave uniformly low RPZ values, and that surprisingly almostindependently of speed and normal force. On the other hand, thecommercial products show an RPZ of 1 or 2 only under certain conditions.This is particularly remarkable, since comparative examples 3M 9343 andtesa 51616 have more than twice or five times the thickness. Moreover,comparative example Tesa 51608, which is more than twice as thick as theexamples according to the invention, shows significantly worse RPZvalues.

EXAMPLE 6 Determination of the Service Life of a Lubricant SystemAccording to the Invention and Comparison with a Commercial LubricantSystem

The test carried out in Example 5 on a stick-slip test bench fromZins-Ziegler was used to determine the long-term stability of thelubricant system according to the invention at a simulated serviceperformance of a car of 60000 km service performance in comparison tothe commercial lubricant system tesa 51616 not according to theinvention. For this purpose, the RPZs are determined after 0 km, 20000km, 40000 km, 60000 km. The RPZ given here is the mean of the RPZs atthe measured parameters given in Example 5 (speed, normal force).

0 km 20000 km 40000 km 60000 km Example 4 1.0 2.4 2.7 2.9 Tesa 51616 3.43.7 4.3 4.3

While the invention has been illustrated and described in detail in thedrawings and foregoing description, such illustration and descriptionare to be considered illustrative or exemplary and not restrictive. Itwill be understood that changes and modifications may be made by thoseof ordinary skill within the scope of the following claims. Inparticular, the present invention covers further embodiments with anycombination of features from different embodiments described above andbelow. Additionally, statements made herein characterizing the inventionrefer to an embodiment of the invention and not necessarily allembodiments.

The terms used in the claims should be construed to have the broadestreasonable interpretation consistent with the foregoing description. Forexample, the use of the article “a” or “the” in introducing an elementshould not be interpreted as being exclusive of a plurality of elements.Likewise, the recitation of “or” should be interpreted as beinginclusive, such that the recitation of “A or B” is not exclusive of “Aand B,” unless it is clear from the context or the foregoing descriptionthat only one of A and B is intended. Further, the recitation of “atleast one of A, B and C” should be interpreted as one or more of a groupof elements consisting of A, B and C, and should not be interpreted asrequiring at least one of each of the listed elements A, B and C,regardless of whether A, B and C are related as categories or otherwise.Moreover, the recitation of “A, B and/or C” or “at least one of A, B orC” should be interpreted as including any singular entity from thelisted elements, e.g., A, any subset from the listed elements, e.g., Aand B, or the entire list of elements A, B and C.

What is claimed is:
 1. A lubricant system for reducing frictional noise,comprising: a textile fabric at least partially embedded in a lubricant,the lubricant comprising a comb polymer having a main polymer chain anda plurality of side chains covalently bonded to the main polymer chain,wherein at least one of the side chains has a molecular weight of atleast 60 g/mol and/or at least 5 repeat units.
 2. The lubricant systemaccording to claim 1, wherein the textile fabric is physically enclosedby the comb polymer.
 3. The lubricant system according to claim 1,wherein the comb polymer is at least partially chemically bonded to thetextile fabric.
 4. The lubricant system according to claim 1, whereinthe lubricant is present as a solid at 20° C.
 5. The lubricant systemaccording to claim 1, wherein at least 10% of the repeat units of themain chain comprise at least one of the side chains.
 6. The lubricantsystem according to claim 1, wherein the main polymer chain has amolecular weight of at least 580 g/mol, and/or at least 8 repeat units.7. The lubricant system according to claim 1, wherein the side chain hasa molecular weight of at least 220 g/mol, and/or at least 5 repeatunits.
 8. The lubricant system according to claim 1, wherein the sidechain of the comb polymer comprises a base oil.
 9. The lubricant systemaccording to claim 1, wherein the comb polymer is obtained bypolymerizing macromonomer having polymerizable functionalities, themacromonomer having at least partially more than one polymerizablefunctionality.
 10. The lubricant system according to claim 9, whereinthe polymerizable functionalities are selected from the group consistingof acrylamide, acrylate, methacrylate, and/or vinyl etherfunctionalities.
 11. The lubricant system according to claim 1, whereinthe comb polymer is present in crosslinked form.
 12. The lubricantsystem according to claim 1, wherein the textile fabric comprises a wetnonwoven.
 13. The lubricant system according to claim 1, wherein thelubricant system has a thickness of from 60 μm to 300 μm and/or a weightof 50 g/m² to 300 g/m².
 14. The lubricant system according to claim 1,wherein the textile fabric contains polyolefin fibers and/or polyesterfibers in a proportion of 50 wt. % to 100 wt. %, based in each case on atotal weight of the textile fabric.
 15. The lubricant system accordingto claim 1, wherein a proportion of comb polymer in the lubricant is 30wt. % to 100 wt. %.
 16. A method for producing the lubricant systemaccording to claim 1, comprising a textile fabric at least partiallyembedded in a lubricant, comprising the following method steps:providing a textile fabric; impregnating and/or coating the textilefabric with a macromonomer-containing coating composition, themacromonomer having a molecular weight of at least 140 g/mol; andpolymerizing the macromonomer to form a comb polymer having a mainpolymer chain and a plurality of side chains covalently bonded to themain polymer chain, at least one of the side chains having a molecularweight of at least 60 g/mol, with a lubricant being formed in which thetextile fabric is embedded, forming the lubricant system.
 17. A methodof using the lubricant system according to claim 1, comprising: usingthe lubricant system to reduce frictional noise from components exposedto frictional loads in a car interior.
 18. The lubricant systemaccording to claim 3, wherein chemically bonded comprises ionicallyand/or covalently bonded.
 19. The lubricant system according to claim 5,wherein 80% to 100% of the repeat units of the main chain comprise atleast one of the side chains.
 20. The lubricant system according toclaim 6, wherein the main polymer chain has a molecular weight of 580g/mol to 50,000 g/mol, and/or 8 to 2000 repeat units.